Process of making gold crowns.



G. H. LELAND.

PROCESS OF MAKING GOLD CROWNS.

APPLICATION FILED FEB. 2| i917.

1,257,357, Patents@ Feb. 26,1918.

fg@ 23W' y# GEORGE HENRY LELAND, F HARTFORD, CONNECTICUT.

PROCESS OF MAKNG GOLD CROWNS.

Application led February 2, 1917.

To all whom t may concern.'

Be it known that l, Grenen HENRY Ln- LND, a citizen of the United States, residing at lil artord. in the county of Hartford and VStato ot Conn tient, have invented certain new and useful improvements in Processes or Making Gold Crowns, or' which the following is a specilication.

My invention relates to improvements in processes of making gold crowns, and the object of my improvement is toproduce a process ot' making gold crowns ir'or dental use involving the reproduction of a die of steel in a casting oi sott metal by the use ot' a mold in which such reproduction is eflected by means ot a special mold of flexible rubber and which mold is adapted for repeated use.

in the accoinpanyingl drawing:-

Figure 1 is a front elevation of the cast torni of sott metal made by my improved process and a finished gold crown mounted thereon.

F ig. 2 is a plan view of the same.

F ig. 3 is a front elevation, on an enlarged scale of the upper part ot' the formshown in Fig. 1, the outline ot the crown being shown in dotted lines.

Fig. a is a side elevation of the same.

Fig. 5 is a front elevation of the blank for the crown', the upper portion being in part broken away,

Fig. 6 is a plan view or' t-l e llask for forming the mold of rubber.

Fig. 7 is a sectional vienV of the flask, the steel die in position therein, 'and the means for supporting the steel die.

Fig. 8 is a similar view after the rubber has been poured into the flask.

Fig. 9 is a similar view of the rubber mold after the metal Jfor the cast form has been poured therein.

Fig. 10 is a view part in section and part in side elevation of the mold.

Fig. 11 is a similar view of the tlask and other parts shown in Fig. 9.

In the use of my process I make use of a die 10 of steel of the'special form from which a copy or reproduction is made of a cast form 11 of soft metal, having a low fusing point, that is used in shaping the gold crown 13 and by my invention I produce a special mold 12 for use in casting the said cast form 11, which mold 12 I produce of sott, flexible rubber, whereby the same is adapted for repeated use.

Specification of Letters Patent.

Patented Feb. 26, 1918.

serial No. 146,234.

The die 10 comprises an elongated structure having the die proper 14 at one end that 1s tormed to correspond approximately to that desired for the linished crown 13having an enlarged base portion 15 at the other end that may be provided with a screw threaded hole 16 for a screw 20 for connecting with a supporting device, which may be 1n the form of a strip 21 of metal, and intermediate the said ends has a generally tapered shank portion 17, the said die 10 being used as ra pattern for casting the cast form 11 in the mold 12. The supportingV strip 21 is narrower than the opening in the flask 18. Y

The Hask 18 consists of an open cup, havi ing a. cylindrical side wall 19, that is of slightly greater depth on the inner side than the die 10 or the portion thereof that it may be desired to reproduce.

In use, the die 10 is inserted into they llask 18 and then the mold 12 is formed around lthe same by pouring into the flask 18 the necessary amount of the proper composition to form the mold 12 of soft rubber, after which the rubber mold 12 is vulcanized.

Then the die 10 and the mold 1'2 are removed from the ilask 18 and the mold 12 is slipped oil from the die 10, and the mold 12 is ready for use.

In such use, the mold 12 is dusted on the interior with powdered soap stone to provide a lining and then the molten soft metal is poured therein to produce the cast form 11.

A s first produced the crown receiving end 22 of the form 11 is an accurate reproduction of the die proper 14;, and before using this for shaping the crown 13, the same is -in most cases modified by cutting away or carving to produce such varied and special form as may be deslred :tor the particular form of the crown.

ber of flasks, a plurality of molds may bev produced at one operation.

The molds are thus produced in sets and d be provided wir-n the set oi' molds oi a id would make his selection oi the indii leual mold in a particular case by the use o'r implements tor determining the size of the tooth and the crown, such itinieter and the shell-gage. Thus from me .surelnents of the sire oit the tooth tiere would be selected a blank for a crov n and also mold that would be most nearly like the finished crown desired, so that a minimum of working over oi" the soft metal casing would be required to obtain the de- 4sired finished form.

Thus means are provided Yfor obtaining a sat factory and supel" mult with a minimum optive netail and in a minimum ot' time, involving a quick and good result.

claim as my invention l.. he process of shaping gold crowns from cup-shaped blanks comprising providing a metal die ot' elongated form having at one end a crown portion oi' arbitrary forni, forming a mold et sott flexible rubber around the said die, producing a metal reproduction of th,n said die l casting in the said mold, operating on the said reproduction by cutting away material thereof so as to produce a modified crown portion to correspond to the shape desired tor the. finished crown, and swaging a blank for the crown on the sain modified crow i portion.

2. rl'he system of shaping gold crowns "rom cup-shaped blanks comprising providi a set oi metal dies having crown portions at. one end ont dirlerent and arbitrary form, selecting from the said set an individual die having a crown portion approximating that desired for the finished crown,

forming a mold of sott, flexible rubber around the said individual die, making a reproduction of the said individual die of metal by casting in the said mold, operating on the said reproduction by cutting away material thereof so as to produce a modified crown portion to correspond to the shape desired for the linished crown, and swaging a blank for the crown on the said modified crown portion.

3. The method of shaping gold crowns `from cup-shaped blanks, comprising providing a set of molds oi soit rubber composed of in 1=ividiml molds having casting openings of different and arbitrary forni, the said casting openings each having the inner end closed and having the inner end portion shaped to correspond approximately to the shape of a tooth crown, providing a blank Jfor a crown, selecting a mold having the inner end portion ot' the casting opening corresponding approximately in size to the size of the said blank, casting a soit metal forni in the said mold, operating on the crown end portion of the said form by cutting away material to produce a modified crown end portion to suit the individual to be 'Hitech and shaping the said blank on the said modified crown end portion.

1i. The method of shaping gold crowns from cup-shaped blanks, comprising` providing a mold of soit rubber having a casting opening and which opening' is closed at the inner end and has a crown portion adjacent the said inner end shaped to correspond approximatelyto the shape of a tooth crown, providing a blank for a crown, casting a soft metal form in the said mold, so as to reproduce the said crown portion at one end of the said form, operating on the said crown portion oi' the form by cutting away material to produce a modiied crown portion suitably to provide individuality thereto, and sha-ping the said blank on the said modified crown portion.

GEGRGE HENRY LELAND.

Witnesses MARION LANPHEAR, `JOI-IN M. BRADY.

Copies of this' patent may be obtained for live cents each, by addressing the Commissioner of Patents,

Washington, D. C. 

